This invention relates generally to fluid actuators for valves and to packing assemblies for a gate valve stem connected to the actuator.
Heretofore, packing assemblies have been provided for gate valve stems connected to actuators for movement of a gate valve between open and closed positions. However, from time to time, packing assemblies for several various reasons have to be replaced and it is difficult and time consuming to replace such packing. A fluid cylinder for the actuator is normally secured to the valve bonnet and a nut receives the stem and holds the packing in a compressed condition. To replace the packing, it is necessary that the fluid cylinder of the actuator be removed first, then the nut is unthreaded to permit access to the separate packing which is then individually removed and replaced. Representative prior art devices are illustrated in U.S. Pat. No. 3,958,592 dated May 25, 1976 and U.S. Pat. No. 3,993,284 dated Nov. 23, 1976.